Robot

ABSTRACT

A walking-on-four-legs type robot whose body is connected at the front right, front left, rear right, and rear left with legs is adapted so that its action saves the user trouble and increases the user&#39;s affection for, and curiosity about, the robot.

TECHNICAL FIELD

[0001] The present invention relates to a robot, and is preferablyapplied to, for example, a walking-on-four-legs type pet robot.

BACKGROUND ART

[0002] The inventor recently developed a walking-on-four-legs type petrobot. The pet robot spontaneously acts in response to an ambientenvironment, the user's action, etc.

[0003] Making such a robot be able to recover from a tumble by itselfsaves the user the work of standing it up and enhances its touch of aliving thing and entertaining characteristics.

[0004] Appealing the loveliness and interest of such a pet robot usingits action increases the user's affection for, and curiosity about, therobot and further enhances its entertaining characteristics.

DISCLOSURE OF THE INVENTION

[0005] The present invention, made in the light of the foregoing,proposes a robot which can enhance entertaining characteristics.

[0006] To solve this problem, a walking-on-four-legs type robot of thepresent invention whose body is connected at the front right, frontleft, rear right, and rear left with legs is provided with driving meansfor driving the legs separately from each other and controlling meansfor controlling the driving means, the controlling means being adaptedto control the driving means so that when the robot tumbles sideward,the driving means turns the forelegs and hind legs under the body insuch directions that the legs open apart from each other and then turnsthe legs in such directions that they move away from the body. Thusbecause the robot can stand up by itself after it falls down, the user'swork of standing it up is eliminated, and its touch of a living thing isincreased, so that entertaining characteristics can be enhanced.

[0007] A walking-on-four-legs type robot of the present invention whosebody is connected at the front right, front left, rear right, and rearleft with legs is provided with driving means for driving the legsseparately from each other and controlling means for controlling thedriving means, the controlling means being adapted to control thedriving means so that when the robot tumbles forward, the driving meansturns the legs at the front of the body until they are almost parallelin front of the body and then turns the legs toward the rear of thebody. Thus because the robot can stand up by itself after it falls down,the user's work of standing it up is eliminated, and its touch of aliving thing is increased, so that entertaining characteristics can beenhanced.

[0008] A walking-on-four-legs type robot of the present invention whosebody is connected at the front right, front left, rear right, and rearleft with legs is provided with driving means for driving the legsseparately from each other and controlling means for controlling thedriving means, the controlling means being adapted to control thedriving means so that when the robot tumbles backward, the driving meansturns the legs at the rear of the body in such directions that the legsmove away from the body until they are almost straight and then turnsthe legs toward the front of the body. Thus because the robot can standup by itself after it falls down, the user's work of standing it up iseliminated, and its touch of a living thing is increased, so thatentertaining characteristics can be enhanced.

[0009] A walking-on-four-legs type robot of the present invention whosebody is connected at the front right, front left, rear right, and rearleft with legs is provided with driving means for driving the legsseparately from each other and controlling means for controlling thedriving means, the controlling means being adapted to control thedriving means so that the driving means opens the legs radially and thenbends the legs above the body. The resulting motion represents a touchof a robot, thus enhancing entertaining characteristics.

[0010] A walking-on-four-legs type robot of the present invention whosebody is connected at the front right, front left, rear right, and rearleft with legs and provided at the front with a head is provided withdriving means for driving the legs and head separately from each otherand controlling means for controlling the driving means, the controllingmeans being adapted to control the driving means so that the end of aleg under the body moves up and down at the back of the head. Theresulting motion allows the robot to appear to scratch the back of itshead, thus appealing a touch of a living thing and enhancingentertaining characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a perspective view showing an arrangement of a pet robotof the embodiment.

[0012]FIG. 2 is a perspective view showing an arrangement of a pet robotof the embodiment.

[0013]FIG. 3 is a block diagram illustrating processing by a controller.

[0014]FIG. 4 is a conceptual view illustrating a probability automaton.

[0015]FIG. 5 is a conceptual view illustrating a condition transitiontable.

[0016]FIG. 6 is a schematic diagram illustrating a pet robot motion.

[0017]FIG. 7 is a schematic diagram illustrating the pet robot motion.

[0018]FIG. 8 is a schematic diagram illustrating the pet robot motion.

[0019]FIG. 9 is a schematic diagram illustrating the pet robot motion.

[0020]FIG. 10 is a schematic diagram illustrating the pet robot motion.

[0021]FIG. 11 is a schematic diagram illustrating the pet robot motion.

[0022]FIG. 12 is a schematic diagram illustrating the pet robot motion.

[0023]FIG. 13 is a schematic diagram illustrating the pet robot motion.

[0024]FIG. 14 is a schematic diagram illustrating the pet robot motion.

[0025]FIG. 15 is a schematic diagram illustrating the pet robot motion.

[0026]FIG. 16 is a schematic diagram illustrating the pet robot motion.

[0027]FIG. 17 is a schematic diagram illustrating the pet robot motion.

[0028]FIG. 18 is a schematic diagram illustrating the pet robot motion.

[0029]FIG. 19 is a schematic diagram illustrating the pet robot motion.

[0030]FIG. 20 is a schematic diagram illustrating the pet robot motion.

[0031]FIG. 21 is a schematic diagram illustrating the pet robot motion.

[0032]FIG. 22 is a schematic diagram illustrating the pet robot motion.

[0033]FIG. 23 is a schematic diagram illustrating the pet robot motion.

[0034]FIG. 24 is a schematic diagram illustrating the pet robot motion.

[0035]FIG. 25 is a schematic diagram illustrating the pet robot motion.

[0036]FIG. 26 is a schematic diagram illustrating the pet robot motion.

[0037]FIG. 27 is a schematic diagram illustrating the pet robot motion.

[0038]FIG. 28 is a schematic diagram illustrating the pet robot motion.

[0039]FIG. 29 is a schematic diagram illustrating the pet robot motion.

[0040]FIG. 30 is a schematic diagram illustrating the pet robot motion.

[0041]FIG. 31 is a schematic diagram illustrating the pet robot motion.

[0042]FIG. 32 is a schematic diagram illustrating the pet robot motion.

[0043]FIG. 33 is a schematic diagram illustrating the pet robot motion.

[0044]FIG. 34 is a schematic diagram illustrating the pet robot motion.

[0045]FIG. 35 is a schematic diagram illustrating the pet robot motion.

[0046]FIG. 36 is a schematic diagram illustrating the pet robot motion.

[0047]FIG. 37 is a schematic diagram illustrating the pet robot motion.

[0048]FIG. 38 is a schematic diagram illustrating the pet robot motion.

[0049]FIG. 39 is a schematic diagram illustrating the pet robot motion.

[0050]FIG. 40 is a schematic diagram illustrating the pet robot motion.

[0051]FIG. 41 is a schematic diagram illustrating the pet robot motion.

[0052]FIG. 42 is a schematic diagram illustrating the pet robot motion.

[0053]FIG. 43 is a schematic diagram illustrating the pet robot motion.

[0054]FIG. 44 is a schematic diagram illustrating the pet robot motion.

[0055]FIG. 45 is a schematic diagram illustrating the pet robot motion.

[0056]FIG. 46 is a schematic diagram illustrating the pet robot motion.

[0057]FIG. 47 is a schematic diagram illustrating the pet robot motion.

[0058]FIG. 48 is a schematic diagram illustrating the pet robot motion.

[0059]FIG. 49 is a schematic diagram illustrating the pet robot motion.

[0060]FIG. 40 is a schematic diagram illustrating the pet robot motion.

[0061]FIG. 51 is a schematic diagram illustrating the pet robot motion.

[0062]FIG. 52 is a schematic diagram illustrating the pet robot motion.

[0063]FIG. 53 is a schematic diagram illustrating the pet robot motion.

[0064]FIG. 54 is a schematic diagram illustrating the pet robot motion.

[0065]FIG. 55 is a schematic diagram illustrating the pet robot motion.

[0066]FIG. 56 is a schematic diagram illustrating the pet robot motion.

[0067]FIG. 57 is a schematic diagram illustrating the pet robot motion.

[0068]FIG. 58 is a schematic diagram illustrating the pet robot motion.

[0069]FIG. 59 is a schematic diagram illustrating the pet robot motion.

[0070]FIG. 60 is a schematic diagram illustrating the pet robot motion.

[0071]FIG. 61 is a schematic diagram illustrating the pet robot motion.

[0072]FIG. 62 is a schematic diagram illustrating the pet robot motion.

[0073]FIG. 63 is a schematic diagram illustrating the pet robot motion.

[0074]FIG. 64 is a schematic diagram illustrating the pet robot motion.

[0075]FIG. 65 is a schematic diagram illustrating the pet robot motion.

[0076]FIG. 66 is a schematic diagram illustrating the pet robot motion.

[0077]FIG. 67 is a schematic diagram illustrating the pet robot motion.

[0078]FIG. 68 is a schematic diagram illustrating the pet robot motion.

[0079]FIG. 69 is a schematic diagram illustrating the pet robot motion.

[0080]FIG. 70 is a schematic diagram illustrating the pet robot motion.

[0081]FIG. 71 is a schematic diagram illustrating the pet robot motion.

[0082]FIG. 72 is a schematic diagram illustrating the pet robot motion.

[0083]FIG. 73 is a schematic diagram illustrating the pet robot motion.

[0084]FIG. 74 is a schematic diagram illustrating the pet robot motion.

[0085]FIG. 75 is a schematic diagram illustrating the pet robot motion.

[0086]FIG. 76 is a schematic diagram illustrating the pet robot motion.

[0087]FIG. 77 is a schematic diagram illustrating the pet robot motion.

[0088]FIG. 78 is a schematic diagram illustrating the pet robot motion.

[0089]FIG. 79 is a schematic diagram illustrating the pet robot motion.

[0090]FIG. 80 is a schematic diagram illustrating the pet robot motion.

[0091]FIG. 81 is a schematic diagram illustrating the pet robot motion.

[0092]FIG. 82 is a schematic diagram illustrating the pet robot motion.

[0093]FIG. 83 is a schematic diagram illustrating the pet robot motion.

[0094]FIG. 84 is a schematic diagram illustrating the pet robot motion.

[0095]FIG. 85 is a schematic diagram illustrating the pet robot motion.

[0096]FIG. 86 is a schematic diagram illustrating the pet robot motion.

[0097]FIG. 87 is a schematic diagram illustrating the pet robot motion.

[0098]FIG. 88 is a schematic diagram illustrating the pet robot motion.

[0099]FIG. 89 is a schematic diagram illustrating the pet robot motion.

[0100]FIG. 90 is a schematic diagram illustrating the pet robot motion.

[0101]FIG. 91 is a schematic diagram illustrating the pet robot motion.

[0102]FIG. 92 is a schematic diagram illustrating the pet robot motion.

[0103]FIG. 93 is a schematic diagram illustrating the pet robot motion.

[0104]FIG. 94 is a schematic diagram illustrating the pet robot motion.

[0105]FIG. 95 is a schematic diagram illustrating the pet robot motion.

[0106]FIG. 96 is a schematic diagram illustrating the pet robot motion.

[0107]FIG. 97 is a schematic diagram illustrating the pet robot motion.

[0108]FIG. 98 is a schematic diagram illustrating the pet robot motion.

[0109]FIG. 99 is a schematic diagram illustrating the pet robot motion.

[0110]FIG. 100 is a schematic diagram illustrating the pet robot motion.

[0111]FIG. 101 is a schematic diagram illustrating the pet robot motion.

[0112]FIG. 102 is a schematic diagram illustrating the pet robot motion.

[0113]FIG. 103 is a schematic diagram illustrating the pet robot motion.

[0114]FIG. 104 is a schematic diagram illustrating the pet robot motion.

[0115]FIG. 105 is a schematic diagram illustrating the pet robot motion.

[0116]FIG. 106 is a schematic diagram illustrating the pet robot motion.

[0117]FIG. 107 is a schematic diagram illustrating the pet robot motion.

[0118]FIG. 108 is a schematic diagram illustrating the pet robot motion.

[0119]FIG. 109 is a schematic diagram illustrating the pet robot motion.

[0120]FIG. 110 is a schematic diagram illustrating the pet robot motion.

[0121]FIG. 111 is a schematic diagram illustrating the pet robot motion.

[0122]FIG. 112 is a schematic diagram illustrating the pet robot motion.

[0123]FIG. 113 is a schematic diagram illustrating the pet robot motion.

[0124]FIG. 114 is a schematic diagram illustrating the pet robot motion.

[0125]FIG. 115 is a schematic diagram illustrating the pet robot motion.

[0126]FIG. 116 is a schematic diagram illustrating the pet robot motion.

[0127]FIG. 117 is a schematic diagram illustrating the pet robot motion.

[0128]FIG. 118 is a schematic diagram illustrating the pet robot motion.

[0129]FIG. 119 is a schematic diagram illustrating the pet robot motion.

[0130]FIG. 120 is a schematic diagram illustrating the pet robot motion.

[0131]FIG. 121 is a schematic diagram illustrating the pet robot motion.

[0132]FIG. 122 is a schematic diagram illustrating the pet robot motion.

[0133]FIG. 123 is a schematic diagram illustrating the pet robot motion.

[0134]FIG. 124 is a schematic diagram illustrating the pet robot motion.

[0135]FIG. 125 is a schematic diagram illustrating the pet robot motion.

[0136]FIG. 126 is a schematic diagram illustrating the pet robot motion.

[0137]FIG. 127 is a schematic diagram illustrating the pet robot motion.

[0138]FIG. 128 is a schematic diagram illustrating the pet robot motion.

[0139]FIG. 129 is a schematic diagram illustrating the pet robot motion.

[0140]FIG. 130 is a schematic diagram illustrating the pet robot motion.

[0141]FIG. 131 is a schematic diagram illustrating the pet robot motion.

[0142]FIG. 132 is a schematic diagram illustrating the pet robot motion.

[0143]FIG. 133 is a schematic diagram illustrating the pet robot motion.

[0144]FIG. 134 is a schematic diagram illustrating the pet robot motion.

[0145]FIG. 135 is a schematic diagram illustrating the pet robot motion.

[0146]FIG. 136 is a schematic diagram illustrating the pet robot motion.

[0147]FIG. 137 is a schematic diagram illustrating the pet robot motion.

[0148]FIG. 138 is a schematic diagram illustrating the pet robot motion.

[0149]FIG. 139 is a schematic diagram illustrating the pet robot motion.

[0150]FIG. 140 is a schematic diagram illustrating the pet robot motion.

[0151]FIG. 141 is a schematic diagram illustrating the pet robot motion.

[0152]FIG. 142 is a schematic diagram illustrating the pet robot motion.

[0153]FIG. 143 is a schematic diagram illustrating the pet robot motion.

[0154]FIG. 144 is a schematic diagram illustrating the pet robot motion.

[0155]FIG. 145 is a schematic diagram illustrating the pet robot motion.

[0156]FIG. 146 is a schematic diagram illustrating the pet robot motion.

[0157]FIG. 147 is a schematic diagram illustrating the pet robot motion.

[0158]FIG. 148 is a schematic diagram illustrating the pet robot motion.

[0159]FIG. 149 is a schematic diagram illustrating the pet robot motion.

[0160]FIG. 150 is a schematic diagram illustrating the pet robot motion.

[0161]FIG. 151 is a schematic diagram illustrating the pet robot motion.

[0162]FIG. 152 is a schematic diagram illustrating the pet robot motion.

[0163]FIG. 153 is a schematic diagram illustrating the pet robot motion.

[0164]FIG. 154 is a schematic diagram illustrating the pet robot motion.

[0165]FIG. 155 is a schematic diagram illustrating the pet robot motion.

[0166]FIG. 156 is a schematic diagram illustrating the pet robot motion.

[0167]FIG. 157 is a schematic diagram illustrating the pet robot motion.

[0168]FIG. 158 is a schematic diagram illustrating the pet robot motion.

[0169]FIG. 159 is a schematic diagram illustrating the pet robot motion.

[0170]FIG. 160 is a schematic diagram illustrating the pet robot motion.

[0171]FIG. 161 is a schematic diagram illustrating the pet robot motion.

[0172]FIG. 162 is a schematic diagram illustrating the pet robot motion.

[0173]FIG. 163 is a schematic diagram illustrating the pet robot motion.

[0174]FIG. 164 is a schematic diagram illustrating the pet robot motion.

[0175]FIG. 165 is a schematic diagram illustrating the pet robot motion.

[0176]FIG. 166 is a schematic diagram illustrating the pet robot motion.

[0177]FIG. 167 is a schematic diagram illustrating the pet robot motion.

[0178]FIG. 168 is a schematic diagram illustrating the pet robot motion.

[0179]FIG. 169 is a schematic diagram illustrating the pet robot motion.

[0180]FIG. 170 is a schematic diagram illustrating the pet robot motion.

[0181]FIG. 171 is a schematic diagram illustrating the pet robot motion.

[0182]FIG. 172 is a schematic diagram illustrating the pet robot motion.

[0183]FIG. 173 is a schematic diagram illustrating the pet robot motion.

[0184]FIG. 174 is a schematic diagram illustrating the pet robot motion.

[0185]FIG. 175 is a schematic diagram illustrating the pet robot motion.

[0186]FIG. 176 is a schematic diagram illustrating the pet robot motion.

[0187]FIG. 177 is a schematic diagram illustrating the pet robot motion.

BEST MODE FOR CARRYING OUT THE INVENTION

[0188] Referring now to the drawings, an embodiment of the presentinvention will be described in detail below.

[0189] (1) Arrangement of Pet Robot 1 According to the Embodiment

[0190] In FIG. 1, a reference numeral 1 generally indicates a pet robotaccording to the embodiment, which robot is arranged by connecting legs3A through 3D to a body 2 at its front right, front left, rear right,and rear left, a head 4 to the front end of the body 2, and a tail 5 tothe rear end of the body 2.

[0191] As shown in FIG. 2, the body 2 contains a controller 10 whichcontrols all actions of the pet robot 1, a battery 11 serving as a powersource for the pet robot 1, an internal sensor unit 14 consisting of abattery sensor 11, an angular velocity sensor 12, an acceleration sensor13, etc., and the like.

[0192] The head 4 is provided in predetermined positions with amicrophone 16 functioning as the ears of the pet robot 1, an externalsensor unit 19 functioning as the eyes which consists of a CCD (chargecoupled device) camera 17, a touch sensor 18, etc., a speaker 20functioning as a mouth, a mouth member 21 functioning as the apparentmouth of the pet robot 1, LEDs (light-emitting diodes), not shown,functioning as the apparent eyes, and the like.

[0193] Lap joint mechanisms 22A through 22D which connect thighs 3AXthrough 3DX and shanks 3AY through 3DY together in the legs 3A through3D, shoulder joint mechanisms 23A through 23D which connect the legs 3Athrough 3D and the body 2 together, a neck joint mechanism 24 whichconnects the body 2 and head 4 together, a chin joint mechanism 25 whichopens or closes the mouth member 21, a tail joint mechanism 26 whichconnects the body 2 and tail 5 together are provided with as manyactuators 27 ₁ through 27 ₁₈ as degrees of freedom required.

[0194] The microphone 16 in the external sensor unit 19 collects soundof the directions “Walk,” “Lie down,” “Follow the ball,” etc. given asscales through a sound commander, not shown, by the user and transmitsan audio signal S1A obtained to a controller 10. The CCD camera 17shoots surrounding scenes and transmits a visual signal S1B obtained tothe controller 10.

[0195] As is clear from FIG. 1, the touch sensor 18 is provided on topof the head 4. The sensor detects pressure due to the user's physicalactions, such as stroking and patting, and transmits the result as apressure detection signal S1C to the controller 10.

[0196] The battery sensor 12 in the internal sensor unit 15 detects theamount of residual charge in the battery 11 and transmits the result asa battery residual charge detection signal S2A to the controller 10. Theangular velocity sensor 13 detects angular velocity for three axes (x,y, and z) and transmits the result as an angular velocity detectionsignal S2B to the controller 10. The acceleration sensor 14 detectsacceleration for the three axes (x, y, and z) and transmits the resultas an acceleration detection signal S2C to the controller 10.

[0197] Based on the audio signal S1A, visual signal S1B, and pressuredetection signal S1C (these signals are hereinafter called externalsensor signals S1 collectively) fed from the microphone 16, CCD camera17, and touch sensor 18 in the external sensor unit 19, respectively,and the battery residual charge detection signal S2A, angular velocitydetection signal S2B, and acceleration detection signal S2C (thesesignals are hereinafter called internal sensor signals S2 collectively)fed from the battery sensor 12, angular velocity sensor 13, andacceleration sensor 14 in the internal sensor unit 15, the controller 10determines the situation around and in the pet robot 1 and whether theuser acts toward the robot.

[0198] Based on the results of determination and a control programstored in memory 10A, the controller 10 determines an action which therobot is to perform and drives actuators 27 ₁ through 27 _(n) accordingto the action to make the robot perform actions, such as vertically andhorizontally swinging the head 4, wagging the tail 5, walking on thelegs 3A through 3D.

[0199] The controller 10 feeds a predetermined audio signal S3 to thespeaker 20 as required to output sound based on the audio signal S3 andflash on and off the LEDs as the apparent eyes.

[0200] As described above, the pet robot 1 is adapted to independentlyact based on the surrounding environment, its own condition, and adirection from the user or his or her action.

[0201] The lap joint mechanisms 22A through 22D in the legs 3A through3D of the pet robot 1 has a degree of freedom of rotation about a pitchaxis parallel to an arrow y in FIG. 1, and the shoulder joint mechanisms23A through 23D freely rotate about the pitch axis parallel to the arrowy in FIG. 1 and a roll axis parallel to an arrow x in FIG. 1.

[0202] This allows the pet robot 1 to move the laps in the legs 3Athrough 3D in forward and backward directions (the forward direction isindicated by the arrow x) within a predetermined range and the entirelegs 3A through 3D in the forward and backward directions and rightwardand leftward directions (the leftward direction is indicated by thearrow y) within predetermined ranges.

[0203] The neck joint mechanism 24 of the pet robot 1 freely rotatesabout the roll axis parallel to the arrow x, the pitch axis parallel tothe arrow y, and a yaw axis parallel to an arrow z in FIG. 1. Thisallows the head 2 to move in the forward, backward, rightward, andleftward directions and an inclination direction within predeterminedranges.

[0204] The tail joint mechanism 26 of the pet robot 1 freely rotatesabout the roll axis parallel to the arrow x and the yaw axis parallel tothe arrow z. This allows the tail 5 to move in the forward, backward,rightward, and leftward directions within predetermined ranges.

[0205] (2) Processing by the Controller 10

[0206] Processing by the controller 10, related to generation of actionof the pet robot 1, will be specifically described below.

[0207] As shown in FIG. 3, basic processing steps performed by thecontroller 10, which are related to generation of action of the petrobot 1, can be functionally assigned to a condition recognizingmechanism 30 which recognizes condition, an emotion/instinct modelingunit 31 which determines the emotional and instinctive condition of thepet robot 1 based on recognition by the condition recognizing mechanism30, a behavior determining mechanism 32 which determines an action basedon recognition by the condition recognizing mechanism 30 and emotion andinstinct modeled by the emotion/instinct modeling unit 31, and abehavior generating mechanism 33 which makes the pet robot 1 behave oract based on determination by the behavior determining mechanism 32.

[0208] Based on the external information signals S1 from the externalsensor unit 19 (FIG. 2) and the internal information signals S2 from theinternal sensor unit 15, the condition recognizing mechanism 30recognizes the condition of surroundings and the pet robot and adirection from the user or his or her action and informs theemotion/instinct modeling unit 31 and behavior determining mechanism 32of the result of recognition as condition recognition information S10.

[0209] Specifically, when the condition recognizing mechanism 30, whichkeeps monitoring audio signals 1A from, for example, the microphone 16in the external sensor unit 19, detects scale sound corresponding to adirection, such as “Walk,” “Lie down,” or “Follow the ball,” itrecognizes the direction and informs the emotion/instinct modeling unit31 and behavior determining mechanism 32 of the recognition.

[0210] When the condition recognizing mechanism 30, which keepsmonitoring an image signal S2A fed from the CCD camera 17, detects ared, round object or a vertical plane in an image based on the imagesignal S2A, the mechanism recognizes that there is a ball or that thereis a wall and informs the emotion/instinct modeling unit 31 and behaviordetermining mechanism 32 of the recognition.

[0211] When the condition recognizing mechanism 30, which keepsmonitoring a pressure detection signal S1B fed from the touch sensor 18,detects a pressure higher than a predetermined threshold value based onthe pressure detection signal S1B for a short time (for example, lessthan two seconds), the mechanism recognizes that the pet robot has beenslapped (or scolded) and informs the emotion/instinct modeling unit 31and behavior determining mechanism 32 of the recognition. On the otherhand, when the condition recognizing mechanism 30 detects a pressureless than the predetermined threshold value for a long time (forexample, two seconds or more), the mechanism recognizes that the petrobot has been stroked (or praised) and informs the emotion/instinctmodeling unit 31 and behavior determining mechanism 32 of therecognition.

[0212] When the condition recognizing mechanism 30, which keepsmonitoring an angular velocity detection signal S2B fed from the angularvelocity sensor 13 in the internal sensor unit 12, detects angularvelocity in the direction of the x, y, and/or z axis based on theangular velocity detection signal S2B, the mechanism recognizes that thepet robot has rotated or inclined in the direction and informs theemotion/instinct modeling unit 31 and behavior determining mechanism 32of the recognition.

[0213] When the condition recognizing mechanism 30, which keepsmonitoring an acceleration detection signal S2C fed from theacceleration sensor 14, detects acceleration in the direction of the x,y, and/or z axis, the mechanism recognizes that the pet robot has movedin the direction and informs the emotion/instinct modeling unit 31 andbehavior determining mechanism 32 of the recognition.

[0214] The emotion/instinct modeling unit 31 has parameters whichrepresent the strength of six emotions, that is, joy, sadness,amazement, horror, disgust, and anger, one parameter for one emotion.The emotion/instinct modeling unit 31 changes the values of theparameters one after another, based on recognition results provided ascondition recognition information S10 by the condition recognizingmechanism 30, behavior determining information S13, which representsdetermined output behavior provided by the behavior determiningmechanism 32 as described later, elapsed time, etc.

[0215] Specifically, the emotion/instinct modeling unit 31 computes thevalue E[t+1] of a parameter of an emotion for the next period atpredetermined time intervals, using the following equation:

E[t+1]=E[t]+k _(e) ×ΔE[t]  (1)

[0216] where ΔE[t] is a change in the emotion computed from apredetermined equation, based on the degree of effect of a recognitionresult obtained based on the condition recognition information 10 andoutput behavior based on the behavior determining information S13 on theemotion (the degree is predetermined), the degree of restriction andstimulus by other emotions, elapsed time, etc., E[t] is the currentvalue of the parameter of the emotion, and k_(e) is a coefficientrepresenting a rate at which the emotion is changed according to therecognition result and the like.

[0217] The emotion/instinct modeling unit 31 updates the current valueE[t] of the parameter of the emotion by replacing it with the result ofcomputation. The emotion of which parameter value should be updated foroutput behavior and a recognition result is predetermined. For example,when the emotion/instinct modeling unit recognizes that the pet robothas been slapped, the value of the parameter of anger increases whilethat of the parameter of joy decreases. When the modeling unitrecognizes that the pet robot has been stroked, the value of theparameter of the joy increases while that of the value of sadnessdecreases.

[0218] Similarly, the emotion/instinct modeling unit 31 has parameterswhich represent the strength of desires independent of each other, thatis, a desire for exercise, a desire for affection, appetite, andcuriosity, one parameter for one desire. The emotion/instinct modelingunit 31 updates the values of the parameters of these desires one afteranother based on recognition by the condition recognizing mechanism 30,elapsed time, information from the behavior determining mechanism 32,and the like.

[0219] Specifically, the emotion/instinct modeling unit 31 computes thevalue I[k+1] of a parameter of a desire, that is, a desire for exercise,a desire for affection, or curiosity, for the next period atpredetermined time intervals, using the following equation:

I[k+1]=I[k]+k _(i) ×ΔI[k]  (2)

[0220] where ΔI[k] is a change in the desire computed from apredetermined equation, based on output behavior of the pet robot 1,elapsed time, the result of recognition, etc., I[k] is the current valueof the parameter of the desire, and k_(i) is a coefficient whichrepresents the sensitivity of the desire. The emotion/instinct modelingunit 31 updates the current value I[k] of the parameter of the emotionby replacing it with the result of computation. The desire of whichparameter value should be changed for a recognition result and outputbehavior is predetermined. For example, when the behavior determiningmechanism 32 informs the modeling unit that some action has been taken,the value of the parameter of a desire for exercise decreases.

[0221] Based on a battery residual charge detection signal S2A (FIG. 2)provided through the condition recognizing mechanism 30, theemotion/instinct modeling unit 31 computes the value I[k+1] of theparameter of appetite from the following equation at a predeterminedtime interval:

I[k]=100−B _(L)  (3)

[0222] where B_(L) is the amount of residual charge in the battery. Theemotion/instinct modeling unit 31 updates the current value I[k] of theparameter of the apetite by replacing it with the result of computation.

[0223] In the embodiment, the values of the parameters of the emotionsand desires are restricted to range from 0 to 100, and the values ofk_(e) and k_(i) are set for each emotion and each desire.

[0224] The behavior determining mechanism 32 determines the next action,based on condition recognition information S10 fed from the conditionrecognizing mechanism 30, the values of the parameters of the emotionsand desires computed by the emotion/instinct modeling unit 31, an actionmodel stored in the memory 10A, elapsed time, etc. and outputs theresult of determination as behavior determining information S12 to theemotion/instinct modeling unit 31 and behavior generating mechanism 33.

[0225] To determine the next action, the behavior determining mechanism32 uses an algorithm, called probability automaton, which determines ona probability basis which of nodes NODE₀ through NODE_(n) the pet robottransits from the node NODE₀ to as shown in FIG. 4, based on transitionprobabilities P₀ through P_(n) set for arcs ARC₀ through ARC_(n)connecting the nodes NODE₀ through NODE_(n) with each other.

[0226] Specifically, the behavior determining mechanism 32 is intendedto determine the next action based on a state transition table 40 whichis stored as an action model for each of the nodes NODE₀ throughNODE_(n) in the memory 10A as shown in FIG. 5.

[0227] In the state transition table 40, input events (results ofrecognition by the condition recognizing mechanism 30), transitionrequirements for the nodes NODE₀ through NODE_(n), are listed on aninput event line in order of priority, and requirements accompanying thetransition requirements are described in corresponding rows in data nameand data range lines.

[0228] For the node NODE₁₀₀ defined in the state transition table 40 inFIG. 5, when a recognition is provided that a ball (BALL) has beendetected, the size (SIZE) of the ball, provided together with therecognition, is required to range from 0 to 1000 (0, 1000), and when arecognition is provided that an obstacle (OBSTACLE) has been detected,the distance (DISTANCE) to the obstacle, provided together with therecognition, is required to range from 0 to 1000 (0, 1000) in order totransit to the node or other nodes.

[0229] For the node NODE₁₀₀ also, even when no recognition is input, itis possible to transit to the node or other nodes if any of theparameters of emotions of joy (JOY), surprise (SURPRISE), and sadness(SUDNESS) in the emotion/instinct modeling unit 31, which parameters areperiodically referred to by the behavior determining mechanism 32,ranges in value from 50 to 1000 (50, 1000).

[0230] In the state transition table 40, the names of nodes to which thepet robot can transit from the nodes NODE₀ through NODE_(n) are listedin the destination node row in the column under “Probability oftransition to other nodes, ” and the probability of transition to thenodes NODE₀ through NODE_(n) as provided when all requirements describedon the input event name, data value, and data range lines are met iswritten on the lines for the nodes NODE₀ through NODE_(n) in the columnunder “Probability of transition to other nodes,” and behavior or actionwhich is output at that time is described on the output behavior line.The sum of the probabilities written on the lines in the column under“Probability of transition to other nodes” is 100%.

[0231] Thus for the node NODE₁₀₀, when a recognition is provided that aball (BALL) has been detected and that the size (SIZE) of the ballranges from 0 to 1000 (0, 1000), the pet robot can transit to the nodeNODE₁₂₀ (node 120) with a probability of 30%. When the robot transits tothe node, behavior or action ACTION 1 is output.

[0232] A behavior model is arranged so that the nodes NODE₀ throughNODE_(n) written in the form of the state transition table 40 succeed.

[0233] As described above, when the state recognition mechanism 30provides the state recognition information S10, or a certain time haselapsed after the last behavior is exhibited, the behavior determiningmechanism 32 determines the next behavior or action (behavior or actiondescribed on the output behavior line) on a probability basis, using thestate transition table 40 for the nodes NODE₀ through NODE_(n) whichcorresponds to a behavior model stored in the memory 10A and outputs theresult of determination as the behavior determination information S12 tothe emotion/instinct modeling unit 31 and behavior generating mechanism33.

[0234] On the other hand, based on the behavior determinationinformation S13 provided by the behavior determining mechanism 32, thebehavior generating mechanism 33 transmits a driving signal S14 (S14 ₁through S14 ₁₈) to necessary actuators 27 ₁ through 27 ₁₈ (FIG. 2), anecessary audio signal S3 to the speaker 20 (FIG. 2), or an LED drivingsignal S15 to the LEDs serving as the eyes.

[0235] As a result, the behavior generating mechanism 33 drives thenecessary actuators 27 ₁ through 27 ₁₈ so that a predetermined conditionis met, based on the driving signal S14; makes the speaker 20 outputsound based on the audio signal S3, or flashes the LEDs on and offaccording to a flash-on and -off pattern based on the LED driving signalS15.

[0236] As described above, based on condition outside or inside the petrobot 1, whether the user acts toward the pet robot 1, etc., thecontroller 10 makes the pet robot 1 behave independently.

[0237] 3) Motions of the Pet Robot 1

[0238] Motions of the pet robot 1 will be described below. The pet robot1 is intended to present a touch of a living thing and a robot throughits motions.

[0239] Motions of the pet robot 1 can be classified into the followingtypes: tumble recovery, or standing up after a tumble; robot, orbehaving like a robot; dog, or behaving like a dog; ball response, orbehavior as observed when the robot finds a ball; emotion expression, orexpressing emotion; idleness, or behavior as observed when the robot isidle; language, or conveying will to the user; and the like.

[0240] By example, these types of motions will be described below.

[0241] (3-1) Tumble Recovery Motions

[0242] Motions which the pet robot 1 makes to stand up when it tumbles(tumble recovery motion) and motions which the pet robot 1 makes aftertumble recovery (post-tumble-recovery motion) will be described below.

[0243] (3-1-1) First Tumble Recovery Motion

[0244] First, a tumble recovery motion which the pet robot 1 makes whenit tumbles to the left as shown in FIG. 6A will be described below.

[0245] When it tumbles leftward, the pet robot 1 first straightens theleft and right forelegs 3A and 3B and left and right hind legs 3C and 3Das shown in FIG. 6A to take a basic upright position and then turns theleft foreleg 3A and left hind leg 3C, which are on the underside due toa tumble, in such directions that the legs open apart from each other,as shown in FIGS. 6B through 6D. In addition to this leg opening motion,the pet robot 1 turns the shank 3AY (FIG. 1) toward the rear to bend theleft foreleg 3A backward and turns the shank 3CY (FIG. 1) toward thefront to bend the left hind leg 3C forward.

[0246] When the pet robot 1 has opened the left foreleg 3A and left hindleg 3C apart to the extent that the thigh 3AX (FIG. 1) in the leftforeleg 3A and the thigh 3CY (FIG. 1) in the left hind leg 3C are almostparallel to each other as shown in FIG. 6D, the robot turns the leftforeleg 3A and left hind leg 3C outside. As a result, the pet robot 1turns as a whole as shown in FIGS. 6E and 6F so that the stomach of thebody 2 comes in contact with the floor, and the right foreleg 3B andright hind leg 3D, which are on the upside due to the fall, come incontact with the floor.

[0247] Then by turning the left foreleg 3A and left hind leg 3C in suchdirections that the legs close together, as shown in FIGS. 7B and 7C,the pet robot 1 brings the left foreleg 3A and left hind leg 3C close tothe body 2 to take the basic upright position.

[0248] Then the pet robot 1 straightens the bent right and left forelegs3B and 3A as shown in FIGS. 7D, 8A, and 8B to stand up in the basicupright position, while slightly moving the center of gravity forward bystraightening the bent right and left hind legs 3D and 3C. This ends themotion.

[0249] (3-1-2) Second Tumble Recovery Motion

[0250] Next, a tumble recovery motion which the pet robot 1 makes whenit tumbles forward as shown in FIG. 9A will be described below.

[0251] When it tumbles forward, the pet robot 1 turns the right and leftforelegs 3B and 3A in such directions that the legs open apart, as shownin FIGS. 9B through 9D, and further turns the right and left forelegs 3Band 3A about their pitch axes to direct toward the floor the contactsurfaces provided by the bottoms of the ends of the legs.

[0252] Next, as shown in FIGS. 9E, 9F, and 10A, the pet robot 1 turnsthe right and left forelegs 3B and 3A in such directions that the legsclose together, while arching the right and left forelegs 3B and 3A sothat their contact surfaces do not come in contact with the floor.

[0253] When this leg closing motion closes the hind right fore leg 3Dand left foreleg 3A until the legs are almost parallel to each other asshown in FIG. 10A, the pet robot 1 brings the right and left forelegs 3Band 3A close to the body 2 by turning the right and left forelegs 3B and3A in such directions that the right foreleg 3B and left foreleg 3A comeclose to the right and left hind legs 3D and 3C, respectively, whileslightly bending the right and left hind legs 3 and 3C to take a lowerposition.

[0254] Then the pet robot 1 gradually straightens the bent right andleft forelegs 3B and 3A and right and left hind legs 3D and 3C to standup in the basic upright position. This ends the motion.

[0255] (3-1-3) Third Tumble Recovery Motion

[0256] Next, a tumble recovery motion which the pet robot 1 makes whenit tumbles backward as shown in FIG. 11A will be described below.

[0257] When it tumbles backward, the pet robot 1 straightens the rightand left forelegs 3B and 3A and right and left hind legs 3D and 3C asshown in FIG. 11A to take the basic upright position and then lifts thehead 4 (FIG. 2) forward as viewed from the pet robot 1, as shown inFIGS. 11B and 11C.

[0258] Next, as shown in FIGS. 11D through 11F, the pet robot 1 turnsthe right and left forelegs 3B and 3A about their pitch axes to make thethighs 3BX and 3AX in them parallel to the direction of gravity, whileturning the right and left hind legs 3D and 3C in such directions thatthe legs open apart until they are almost parallel to each other. Thiscauses the pet robot 1 to gradually tumble forward under the action ofgravity.

[0259] When the right and left hind legs 3D and 3C open apart until thelegs are almost parallel to each other, as shown in FIG. 12A, and theright and left forelegs 3B and 3A come in contact with the floor, thepet robot 1 turns the right and left hind legs 3D and 3C in suchdirections that the legs close together, while bending them, as shown inFIGS. 12B through 12F.

[0260] Then when the pet robot 1 closes the right and left hind legs 3Dand 3C together until they are almost parallel to each other, as shownin FIG. 13A, the robot brings the right and left hind legs 3D and 3Cclose to the body 2 by turning these legs in such directions that theright and left hind legs 3D and 3C come close to the right foreleg 3Band left foreleg 3A, respectively and then straightens the bent rightand left hind legs 3D and 3C to take the basic upright position. Thisends the motion.

[0261] (3-1-4) First Post-tumble-recovery Motion

[0262] Next, a motion which the pet robot 1 makes will be describedbelow.

[0263] When the pet robot 1 takes the basic upright position with thetumble recovery motion described above as shown in FIG. 14A, it movesthe center of gravity to prevent its weight from acting on the leftforeleg 3A (or the right foreleg 3B) and then lifts the left foreleg 3A(or the right foreleg 3B) by turning forward, as shown in FIGS. 14Cthrough 14F. The pet robot 1 turns the thigh 3AY (3BY) in the leftforeleg 3A (or the right foreleg 3B) toward the rear to bend the leftforeleg 3A (or the right foreleg 3B). In addition, the pet robot 1 turnsthe head 4 through a predetermined angle to the right (or the left) asviewed from the pet robot 1.

[0264] Then when the contact surface of the left foreleg 3A (or theright foreleg 3B) comes close to the back of the head 4 as shown in FIG.15A, the pet robot 1 turns the shank 3AY (3BY) in the left foreleg 3A(or the right foreleg 3B) through a predetermined angle a few timestoward the front and rear of the pet robot 1.

[0265] After this action is completed, the pet robot performs thereverse of the actions shown in FIGS. 14A through 14F to return to theupright position. This ends the motion.

[0266] Such a motion can produce a feeling that the pet robot 1scratches the back of the head 4 in embarrassment because it tumbles,thus giving the user a lovely impression.

[0267] (3-1-5) Second Post-tumble-recovery Motion

[0268] Next, a second post-tumble-recovery motion which the pet robot 1makes will be described below.

[0269] After it takes the basic upright position with the tumblerecovery motion described above as shown in FIG. 17A, the pet robot 1slightly bends the right and left forelegs 3B and 3A and right and lefthind legs 3D and 3C as shown in FIG. 17B to take a lower position andturns the head 4 toward its front as shown in FIG. 17C to direct thehead 4 downward.

[0270] Then the pet robot 1 turns the head 4 to the right and left a fewtimes as shown in FIGS. 17D through 18A. Next, the robot straightens theright and left forelegs 3B and 3A and the right and left hind legs 3Dand 3C to return to the basic upright position. This ends the motion.

[0271] Such a motion can produce a feeling that the pet robot 1 swingsthe head 4 to the right and left to refresh, thus giving the user alovely impression.

[0272] (3-1-6) Other Tumble Recovery Motions

[0273]FIGS. 19A through 20F show the flow of a tumble recovery motionwith which the pet robot 1 stands up after it tumbles rightward. Thetumble recovery motion is the same as the first tumble recovery motionexcept that the former is opposite in direction to the latter.

[0274] (3-2) Robot Language Motions

[0275] Robotlike actions will be described below which the pet robot 1performs when the condition recognizing mechanism 30 (FIG. 3) in thecontroller 10 (FIG. 2) does not provide a specific recognition result(such actions are hereinafter called robot language motions).

[0276] (3-2-1) First Robot Language Motion

[0277] First, a first robot language motion will be described below.When the pet robot 1 is in a basic down position, it produces the firstrobot language motion.

[0278] When the pet robot 1 is in a down position, with the right andleft forelegs 3B and 3A extended toward its front, as shown in FIG. 21A,the robot turns the right and left forelegs 3B and 3A in such directionsthat the legs open apart, as shown in FIGS. 21B and 21C. In addition, asshown in FIGS. 21B through 21E, the pet robot 1 extends the right andleft hind legs 3D and 3C toward the front and then turns these legstoward its rear to radially extend them. As a result, the pet robot 1takes such a position that the right and left forelegs 3B and 3C andright and left hind legs 3A and 3D form a cross, as shown in FIG. 21F.When the right and left hind legs 3D and 3C open apart until they arealmost parallel to each other, the pet robot 1 turns the right and lefthind legs 3D and 3C approximately 180° about their pitch axes.

[0279] Then as shown in FIGS. 22A through 22E, the pet robot 1 lifts theright and left forelegs 3B and 3A and the right and left hind legs 3Dand 3C above itself, while bending these legs. In parallel, the petrobot 1 bends the head 4 toward its rear to lift the head 4, opens themouth, and lifts the tail 5 above itself to bend the entire body.

[0280] Then as shown in FIGS. 22F through 23D, the pet robot 1 performsthe reverse of the actions in FIGS. 21F through 22E to return to itsoriginal position as shown in FIG. 23D. Next, the pet robot 1 performsthe same action as in FIGS. 21F through 23D twice or three times.

[0281] Then as shown in FIGS. 23E through 24C, the pet robot 1 performsthe reverse of the actions in FIGS. 21A through 21E to return to thedown position. This ends the motion.

[0282] Such a motion shows a touch of a robot.

[0283] (3-2-2) Second Robot Language Motion

[0284] Next, a second robot language motion will be described below.When the pet robot 1 is in a basic down position as shown in FIG. 25A,it produces the second robot language motion.

[0285] When it is in the down position as shown in FIG. 25A, the petrobot 1 acts as shown in FIGS. 25A through 27A as is the case with thefirst robot language motion illustrated in FIGS. 21A through 21F to takesuch a position that the right foreleg 3B and the left hind leg 3C andthe left foreleg 3A and the right hind legs 3D form a cross, as shown inFIG. 27A.

[0286] Then as shown in FIGS. 27B through 28D, the pet robot 1alternately turns a combination of the right foreleg 3B and the righthind leg 3C and a combination of the left foreleg 3A and the right hindleg 3D through a predetermined angle a few times so that the angle doesnot change which is made by a straight line formed by the right foreleg3B and the left hind leg 3C and one formed by the left foreleg 3A andthe right hind leg 3D.

[0287] When the combination of the right foreleg 3B and the left hindleg 3C and that of the left foreleg 3A and the right hind leg 3D takesthe position in FIG. 27A as shown in FIG. 28F after the action iscompleted, the pet robot 1 performs the reverse of the actions in FIGS.25A through 27A as shown in FIGS. 29A through 30B to return to theoriginal down position. This ends the motion.

[0288] Such a motion shows a touch of a robot.

[0289] (3-2-3) Third Robot Language Motion

[0290] A third robot language motion will be described below. The petrobot 1 produces the third robot language motion as performance inresponse to a direction from the user.

[0291] When it is in the basic down position as shown in FIG. 31A, thepet robot 1 slightly opens the right and left hind legs 3D and 3C apartoutside as shown in FIG. 31B and then lifts the right and left hind legs3D and 3C to the extent that the ends of these legs are a little abovethe shoulders as shown in FIGS. 31C through 31F.

[0292] Then as shown in FIGS. 32A through 32F, the pet robot 1 turns theright and left hind legs 3D and 3C one after the other a plurality oftimes in such directions that the legs open and close to swing the rightand left hind legs 3D and 3C a plurality of times.

[0293] After this action is completed, the pet robot 1 lowers the rightand left hind legs 3D and 3C until they are extended forward as shown inFIGS. 33A through 33C and then removes the legs inside to return to theoriginal down position. This ends the motion.

[0294] Such a motion shows a touch of a robot.

[0295] (3-2-4) Other Robot Language Motions

[0296]FIGS. 34A through 35C, 36A through 37E, 38A through 39F, and 40Athrough 42E show other robot language motions, that is, fourth, fifth,sixth, and seventh robot language motions, respectively.

[0297] (3-3) Dog Motions

[0298] Next, doglike motions will be described below which the pet robot1 makes when the condition recognizing mechanism 30 (FIG. 3) in thecontroller 10 (FIG. 2) does not provide a specific recognition result(these motions are hereinafter called dog motions).

[0299] (3-3-1) First Dog Motion

[0300] A first dog motion will be described below. When the pet robot 1is in a basic down position as shown in FIG. 43A, it produces the firstdog motion.

[0301] When it is in the down position, with the right and left forelegs3B and 3A extended forward as shown in FIG. 43A, the pet robot 1slightly moves the left hind leg 3C (or the right hind leg 3D) outsideas shown in FIGS. 43B and 43C to open it and then lifts the left hindleg 3C (or the right hind leg 3D) as shown in FIGS. 43D through 43F. Inparallel, the pet robot 1 turns the head 4 to direct it off to the upperright forward (or off to the upper left forward).

[0302] Then when the contact surface of the left hind leg 3C (or theright hind leg 3D) has risen to the back of the head 4, the pet robot 1vertically turns the left hind leg 3C (or the right hind leg 3D) twiceor three times as shown in FIGS. 43F through 44C to scratch the back ofthe head 4 with the left hind leg 3C (or the right hind leg 3D).

[0303] Next, the pet robot lowers the left hind leg 3C (or the righthind leg 3D) as shown in FIGS. 44D through 44F and then moves the lefthind leg 3C (or the right hind leg 3D) to return it inside, thus takingthe original down position. This ends the motion.

[0304] Such a motion can produce a feeling that the pet robot 1scratches the back of the head 4, thus giving the user a doglikeimpression.

[0305] (3-3-2) Second Dog Motion

[0306] Next, a second dog motion will be described below. When the petrobot 1 is in an upright position as shown in FIG. 46A, it produces thesecond dog motion.

[0307] As shown in FIG. 46B, the pet robot 1 moves the center of gravityso that its weight does not act on the right hind leg 3D (or the lefthind leg 3C). Next, the pet robot 1 slightly moves the right hind leg 3D(or the left hind leg 3C) outside to open the leg and then lifts theright hind leg 3D (or the left hind leg 3C) above the robot itself. Whendoing so, the pet robot 1 bends the knee 3DY (or 3CY) in the right hindleg 3D (or the left hind leg 3C) to the extent that the thighs 3DX (or3CY) and shank 3DY (or 3CY) are at right angles to each other.

[0308] After sound of running water is output from the speaker 20 (FIG.2) for two to three seconds, the pet robot 1 performs the reverse of theactions in FIGS. 46A through 47A as shown in FIGS. 47B through 47E totake the original upright position. This ends the motion.

[0309] Such a motion can produce a feeling that the pet robot 1 piddles,thus giving the user a doglike impression.

[0310] (3-3-3) Other Dog Motions

[0311]FIGS. 48A through 51C, 52A through 54A, 55A through 58A, and 59Athrough 61C show the flow of other dog motions, that is, third, fourth,fifth, and sixth dog motions, respectively.

[0312] (3-4) Ball Response Motions

[0313] Motions which the pet robot 1 produces when it finds a fall willbe described below (these motions are hereinafter called ball responsemotions).

[0314] (3-4-1) First Ball Response Motion

[0315] A first ball response motion will be described below. When thepet robot 1 finds a ball, it produces the first ball response motion.

[0316] When it finds a ball, the pet robot 1 walks close to the ball tothe extent that the ball is just in front of the left foreleg 3A (or theright foreleg 3B) and then takes an upright position as shown in FIG.62A.

[0317] Next, as shown in FIG. 62B, the pet robot 1 moves the center ofgravity so that its weight does not act on the left foreleg 3A (or theright foreleg 3B) and then turns the left foreleg 3A (or the rightforeleg 3B) through a predetermined angle toward the rear as shown inFIGS. 62C through 62F to bring the left foreleg 3A (or the right foreleg3B) close to the left hind leg 3C (or the right hind leg 3D). Inparallel, the pet robot 1 inclines the head 4 toward a position just infront of the left foreleg 3A (or the right foreleg 3B) as if to look atthe ball.

[0318] The pet robot 1 dynamically turns the left foreleg 3A (or theright foreleg 3B) toward the front, while extending the withdrawn leftforeleg 3A (or right foreleg 3B), as shown in FIGS. 63A through 63D.Next, as shown in FIGS. 63E through 64B, the pet robot 1 lowers the leftforeleg 3A (or the right foreleg 3B) to return it to the originalposition and then straightens the bent right foreleg 3B (or left foreleg3A), right hind leg 3D, and left hind leg 3C to take the uprightposition. This ends the motion.

[0319] Such a motion, with which the pet robot 1 can kick a ball, canproduce a feeling that the pet robot 1 plays with a ball.

[0320] (3-4-2) Second Ball Response Motion

[0321] Next, a second ball response motion will be described below.

[0322] When it finds a ball in the surroundings, the pet robot 1 walksclose to the ball until the ball is slightly off the front to the left(or the right) and then takes a basic upright position as shown in FIG.65A.

[0323] Then the pet robot 1 bends the right and left forelegs 3B and 3Aand right and left hind legs 3D and 3C as shown in FIGS. 65B and 65C totake a lower position and turns the head 4 toward the front to directthe head 4 downward.

[0324] Next, the pet robot turns the head 4 to the right (or the left),while drawing the chin and then dynamically turns the head 4 off to theleft (or right) forward, where the ball is, as shown in FIGS. 65Fthrough 67B. Finally, as shown in FIGS. 67C and 67D, while adjusting thehead 4 so that it faces the front, the pet robot 1 straightens the bentright and left forelegs 3B and 3A and the bent right and left hind legs3D and 3C to return to the original upright position. This ends themotion.

[0325] Such a motion, with which the pet robot can head a ball, canproduce a feeling that the pet robot 1 plays with a ball.

[0326] (3-4-3) Third Ball Response Motion

[0327] Next, a second ball response motion will be described below. Whenthe pet robot 1 finds a ball, it produces the third ball responsemotion.

[0328] When it finds a ball, the pet robot 1 walks close to a positionimmediately behind the ball and then takes a basic upright position asshown in FIG. 68A.

[0329] Next, the pet robot 1 draws back its entire body, while loweringitself by bending the right and left hind legs 3D and 3C, as shown inFIG. 68B. In parallel, the pet robot 1 turns the head 4 from the rear tothe front to lower the head 4 sharply until the top of the head 4 facesforward.

[0330] In addition, while bending the knees, the pet robot 1 turns theright and left forelegs 3B and 3A toward the rear to squeeze itself.Then as shown in FIGS. 69A through 69E, the pet robot 1 turns the head 4toward the rear to push the ball forward, while dynamically extendingthe bent right and left hind legs 3D and 3C to slightly move the entirebody forward.

[0331] Finally, the pet robot 1 slightly straightens the right and leftforelegs 3B and 3A and the right and left hind legs 3D and 3C as shownin FIG. 69F to return to the original upright position. This ends themotion.

[0332] Such a motion, with which the pet robot 1 can head a ball, canproduce a feeling that the pet robot 1 plays with a ball.

[0333] (3-4-4) Fourth Ball Response Motion

[0334] Next, a fourth ball response motion will be described below.

[0335] When it finds a ball, the pet robot 1 walks close to the balluntil the ball is just in front of the robot and then takes a basicupright position as shown in FIG. 70A.

[0336] Next, the pet robot 1 moves the center of gravity so that itsweight does not act on the left foreleg 3A and then positions thecontact surface of the left foreleg 3A a little above the ball bylifting the left foreleg 3A so that the end of the leg draws an arcoutward.

[0337] Then the pet robot 1 brings the contact surface of the leftforeleg 3A in contact with the ball from above by turning the shank inthe left foreleg 3A downward. Finally, the pet robot 1 performs thereverse of the actions in FIGS. 70A through 70F as shown in FIGS. 71Bthrough 72B to return to the original down position. This ends themotion.

[0338] Such a motion can produce a feeling that the pet robot 1 playswith a ball with interest, thus giving the user a lifelike impression.

[0339] (3-4-5) Other Ball Response Motions

[0340]FIGS. 73A through 74E, 75A through 77F, 78A through 80D, and 81Athrough 83B show other ball response motions, that is, fifth, sixth,seventh, and eighth ball response motions, respectively.

[0341] (3-5) Emotion Expression Motion

[0342] Next, motions with which the pet robot 1 expresses emotion willbe described below (these motions are hereinafter called emotionexpression motions).

[0343] (3-5-1) First Emotion Expression Motion

[0344] A first emotion expression motion will be described below. Thepet robot 1 produces the first emotion expression motion when it isdown, with the right and left hind legs 3D and 3C straightened forward,and, for example, a loud sound occurs in the neighborhood, or an objectsuddenly appears before the robot.

[0345] That is, when the pet robot 1 is down as shown in FIG. 84A, and,for example, a loud sound occurs in the neighborhood, or an objectsuddenly appears before the robot, it lifts the right and left hind legs3D and 3C slightly for an instant. In parallel, the pet robot 1 turnsthe head 4 back for an instant, bending the head 4, opens the mouth, andstands the tail 5 for an instant. Then the pet robot 1 returns to theoriginal down position as shown in FIG. 84C.

[0346] Such a motion can produce a feeling that the pet robot 1 isstartled, thus expressing an emotion of surprise.

[0347] (3-5-2) Second Emotion Expression Motion

[0348] Next, a second emotion expression motion will be described below.The pet robot 1 produces the second emotion expression motion when itexpresses an emotion of anger.

[0349] When it is in a basic upright position as shown in FIG. 85A, thepet robot 1 moves the center of gravity so that its weight does not acton the right foreleg 3B (or the left foreleg 3A), as shown in FIGS. 85Band 85C and then swing the entire right foreleg 3B (or left foreleg 3A)back and forth of the pet robot, and in concert with this swings theshank 3BY (3AY) in the right foreleg 3B (or the left foreleg 3A) backand forth as shown in FIGS. 85D through 86F to act as if it scratchesthe floor a few times. In parallel, the pet robot 1 directs the head 4downward, generating a feeling that it looks at the floor and flashes onand off a red LED, which has a shape appearing to express anger andfunctions as an eye.

[0350] After this action is completed, the pet robot 1 performs thereverse of the actions in FIGS. 85A through 85C as shown in FIGS. 87Athrough 87D to return to the original upright position. This ends themotion.

[0351] Such a motion can produce a feeling that the pet robot 1scratches the ground with anger, thus expressing an emotion of anger.

[0352] (3-5-3) Third Emotion Expression Motion

[0353] Next, a third emotion expression motion will be described below.The pet robot 1 produces the third emotion expression motion when itfeels a dislike.

[0354] When the pet robot 1 is in a basic down position as shown in FIG.88A, it lifts the right and left forelegs 3B and 3A as shown in FIGS.88B through 88D so that the thighs 3BX and 3AX nearly level and turnsthe head 4 to the right (or left) to direct it to the right (or left).Here the pet robot 1 bends the knee 3BY to the extent that the contactsurface of the right foreleg 3B faces forward and bends the knee 3AY inthe left foreleg 3A more sharply than the knee 3BY.

[0355] Then the pet robot 1 turns the left foreleg 3A (or the rightforeleg 3B) as it is from side to side a plurality of times as if toswing the leg, as shown in FIGS. 88E through 90A. After this action iscompleted, the pet robot 1 performs the reverse of the actions in FIGS.88A through 88D as shown in FIGS. 90B through 90D to return to theoriginal down position. This ends the motion.

[0356] Such a motion can produce a feeling that the pet robot 1 shows adislike, thus giving the user a lifelike impression.

[0357] (3-5-4) Other Emotion Expression Motions

[0358]FIGS. 91A through 93A, 94A through 96A, 97A through 98E, 99Athrough 99C, 100A through 102A, 103A through 105E, and 106A through 107Dshow the flow of other emotion expression motions, that is, fourth,fifth, sixth, seventh, eighth, ninth, and tenth emotion expressionmotions, respectively.

[0359] (3-6) Idleness Motions

[0360] Next, motions will be described below which the pet robot 1produces when the condition recognizing mechanism 30 (FIG. 3) in thecontroller 10 (FIG. 2) does not provide a specific recognition result(these motions are hereinafter called idleness motions).

[0361] (3-6-1) First Idleness Motion

[0362] A first idleness motion will be described below. The pet robot 1produces the first idleness motion when it is in a basic down positionas shown in FIG. 108A.

[0363] When the pet robot 1 is in the basic down position as shown inFIG. 108A, it slowly lifts the right and left forelegs 3B and 3A, whileopening them apart outside, as shown in FIGS. 108B through 109C. Inparallel, the pet robot 1 bends the right foreleg 3B and shank 3AY inthe left foreleg 3A backward. Here the pet robot 1 is supported by therear end of the stomach of the body 2 and right and left hind legs 3Dand 3C.

[0364] After lifting the thighs 3BX and 3AX in the right and leftforelegs 3B and 3A until they nearly level, as shown in FIG. 109C, thepet robot 1 opens the mouth, while bending the head 4 backward, as shownin FIGS. 109D through 111B. In parallel, while straightening the rightand left forelegs 3B and 3A and moving them back in such directions thatthe legs close together, the pet robot 1 turns the legs down.

[0365] Then when the right and left forelegs 3B and 3A come in contactwith the floor as shown in FIG. 111C, the pet robot 1 directs the head 4forward to return to the original down position. This ends the motion.

[0366] Such a motion can produce a feeling that the pet robot 1 yawns,stretching itself, thus giving the user a lifelike impression.

[0367] (3-6-2) Second Idleness Motion

[0368] Next, a second idleness motion will be described below. The petrobot 1 produces the second idleness motion when it slightly opens theright and left hind legs 3D and 3C outward and straightens them forwardas shown in FIG. 112A.

[0369] When the pet robot 1 is as shown in FIG. 112A, it turns the head4 to draw a circle, as shown in FIGS. 112B through 113A. Here the mouthis open.

[0370] Once the head 4 faces slightly up forward as shown in FIG. 113B,the pet robot 1 dynamically turns the head 4 obliquely down as shown inFIGS. 113C through 113F. Here the speaker 20 (FIG. 2) outputs a sound ofsneezing.

[0371] When the head 4 faces downward, the pet robot 1 swings the head 4from side to side a few times. After completing the action, the petrobot 1 directs the head 4 as before to return to the original downposition. This ends the motion.

[0372] Such a motion can produce a feeling that the pet robot 1 sneezes,thus giving the user a lifelike impression.

[0373] (3-6-3)

[0374]FIGS. 116A through 119E, 120A through 124A, 125A through 127A,128A through 130B, 131A through 133A, and 134A through 136E show theflow of other idleness motions, that is, third, fourth, fifth, sixth,seventh, and eighth idleness motions, respectively.

[0375] (3-7) Language Motions

[0376] Next, language motions will be described below which the petrobot 1 produces when it wants to inform the user of something (thesemotions are hereinafter called language motions).

[0377] (3-7-1) First Language Motion

[0378] A first language motion will be described below. The pet robot 1produces the first language motion when it is in a basic down positionas shown in FIG. 137A.

[0379] When the pet robot 1 is in the basic down position in FIG. 137A,it lifts the right and left forelegs 3B and 3A almost to the level ofthe shoulders as shown in FIGS. 137B through 137E and then lowers theright and left forelegs 3B and 3A so that their ends draw an arc, asshown in FIGS. 137F through 138E.

[0380] Then after slightly inclining the head 4 to the left (or right)as shown in FIGS. 138F through 140B, the pet robot 1 moves the right andleft forelegs 3B and 3A up and down a few times. After completing thisaction, the pet robot 1 brings the right and left forelegs 3B and 3A incontact with the floor to return to the original down position, as shownin FIG. 140C. This ends the motion.

[0381] With such a motion, the pet robot 1 can indicate a ball as shownin FIGS. 137B through 137E and express a want to convey a desire for aball to the user.

[0382] (3-7-2) Other Language Motions

[0383]FIGS. 141A through 143A, 144A through 147E, 148A through 150F,151A through 154A, 155A through 157A, and 158A through 161A show otherlanguage motions, that is, second, third, fourth, fifth, sixth, andseventh language motions, respectively.

[0384] (3-8) Other Motions

[0385]FIGS. 162A through 165A, 166A through 168E, 169A through 171F,172A through 174D, and 175A through 177D show the flow of motions whichthe pet robot 1 produces when it grows up (these motions are hereinaftercalled growth motions), that is, first, second, third, fourth, and fifthgrowth motions, respectively, as examples of other motions.

[0386] (4) Effect of the Embodiment

[0387] With motions, the pet robot 1 arranged as described aboverecovers from a tumble and presents a touch of a living thing or arobot.

[0388] Thus the pet robot 1 eliminates the need for the user to standthe robot when it tumbles. In addition, the robot gives the useraffection for, and curiosity about, it with motions.

[0389] Because the pet robot 1 is adapted so that it recovers from atumble and presents a touch of a living thing or a robot with motions,the arrangement eliminates the need for the user to stand up the petrobot 1 when it tumbles and allows the pet robot 1 to give the useraffection for, and curiosity about, the robot with motions, thusenhancing the amusing characteristics of the pet robot 1.

[0390] (5) Other Embodiments

[0391] In the above-described embodiment, the present invention isapplied to the pet robot 1 arranged as shown in FIG. 1. However, thepresent invention is not limited to such an arrangement but can beapplied to a variety of robots.

[0392] Industrial Applicability

[0393] The present invention can be applied to pet robots.

1. A walking-on-four-legs type robot whose body is connected at thefront right, front left, rear right, and rear left with legs,characterized in that said robot comprises: driving means for drivingthe legs separately from each other; and controlling means forcontrolling the driving means, and said controlling means controls thedriving means so that when the robot tumbles sideward, the driving meansturns the forelegs and hind legs under the body in such directions thatthe legs open apart from each other and then in such directions thatthey move away from the body.
 2. A walking-on-four-legs type robot whosebody is connected at the front right, front left, rear right, and rearleft with legs, characterized in that said robot comprises: drivingmeans for driving the legs separately from each other; and controllingmeans for controlling the driving means, and said controlling meanscontrols the driving means so that when the robot tumbles forward, thedriving means turns the legs at the front of the body until they areparallel in front of the body and then turns the legs toward the rear ofthe body.
 3. A walking-on-four-legs type robot whose body is connectedat the front right, front left, rear right, and rear left with legs,characterized in that said robot comprises: driving means for drivingthe legs separately from each other; and controlling means forcontrolling the driving means, and said controlling means controls thedriving means so that when the robot tumbles backward, the driving meansturns the legs at the rear of the body in such directions that the legsmove away from the body until they are almost straight and then turnsthe legs toward the front of the body.
 4. A walking-on-four-legs typerobot whose body is connected at the front right, front left, rearright, and rear left with legs, characterized in that said robotcomprises: driving means for driving the legs separately from eachother; and controlling means for controlling the driving means, and saidcontrolling means controls the driving means so that the driving meansopens the legs radially and then bends the legs above the body.
 5. Awalking-on-four-legs type robot whose body is connected at the frontright, front left, rear right, and rear left with legs and provided atthe front with a head, characterized in that said robot comprises:driving means for driving the legs and head separately from each other;and controlling means for controlling the driving means, and saidcontrolling means controls the driving means so that the end of one ofsaid legs under the body moves up and down at the back of the head.